《Flask Web开发》学习笔记之bug--（9）【jinja2.exceptions.TemplateSyntaxError: unexpected '%'】

/app/main/views.py

from flask import render_template, session, redirect, url_for, current_app
from .. import db
from ..models import User
from ..email import send_email
from . import main
from .forms import NameForm


@main.route('/', methods=['GET', 'POST'])
def index():
	form = NameForm()
	if form.validate_on_submit():
		user = User.query.filter_by(username=form.name.data).first()
		if user is None:
			user = User(username=form.name.data)
			db.session.add(user)
			session['known'] = False
			if current_app.config['FLASKY_ADMIN']:
				send_mail(current_app.config['FLASKY_ADMIN'], \
					'New User', 'mail//new_user', user=user)
		else:
			session['known'] = True
		session['name'] = form.name.data
		return redirect(url_for('.index'))
	return render_template('index.html', form=form, name=session.get('name'), known=session.get('known', False))

/app/templates/base.html

{% extends "bootstrap/base.html" %}

{% block title %}Flasky{% endblock %}

{% block head %}
{{ super() }}


{% endblock %}

{% block navbar %}

	

		

			
				Toggle navigation
				
				
				
			
			Flask
		
		

			

				{% if current_user.is_authenticated() %}
				
Sign Out
				{% else %}
				
Sign In
				{% endif %}
			
		
	

{% endblock %}

{% block content %}

	{% for message in get_flashed_messages() %}
	

		×
		{{ message }}
	
	{{% endfor %}}

	{% block page_content %}{% endblock %}

{% endblock %}

{% block scripts %}
{{ super() }}
{{ moment.include_moment() }}
{% endblock %}

报错信息：

$ python3 manage.py runserver --host 0.0.0.0
/home/henry/.local/lib/python3.5/site-packages/flask_sqlalchemy/__init__.py:800: UserWarning: SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future.  Set it to True to suppress this warning.
  warnings.warn('SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future.  Set it to True to suppress this warning.')
 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
 * Restarting with stat
/home/henry/.local/lib/python3.5/site-packages/flask_sqlalchemy/__init__.py:800: UserWarning: SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future.  Set it to True to suppress this warning.
  warnings.warn('SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future.  Set it to True to suppress this warning.')
 * Debugger is active!
 * Debugger PIN: 187-944-274
127.0.0.1 - - [17/Jul/2017 17:26:10] "GET / HTTP/1.1" 500 -
Traceback (most recent call last):
  File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1997, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1985, in wsgi_app
    response = self.handle_exception(e)
  File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1540, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/henry/.local/lib/python3.5/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1517, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/henry/.local/lib/python3.5/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/henry/dev/Flask_Web_Python_Henry/flask_henry/app/main/views.py", line 25, in index
    return render_template('index.html', form=form, name=session.get('name'), known=session.get('known', False))
  File "/home/henry/.local/lib/python3.5/site-packages/flask/templating.py", line 134, in render_template
    context, ctx.app)
  File "/home/henry/.local/lib/python3.5/site-packages/flask/templating.py", line 116, in _render
    rv = template.render(context)
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 1008, in render
    return self.environment.handle_exception(exc_info, True)
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 780, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/_compat.py", line 37, in reraise
    raise value.with_traceback(tb)
  File "/home/henry/dev/Flask_Web_Python_Henry/flask_henry/app/templates/base.html", line 43, in template
    {{% endfor %}}
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 1005, in render
    return concat(self.root_render_func(self.new_context(vars)))
  File "/home/henry/dev/Flask_Web_Python_Henry/flask_henry/app/templates/index.html", line 1, in top-level template code
    {% extends "base.html" %}
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 780, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/_compat.py", line 37, in reraise
    raise value.with_traceback(tb)
  File "/home/henry/dev/Flask_Web_Python_Henry/flask_henry/app/templates/base.html", line 43, in template
    {{% endfor %}}
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 497, in _parse
    return Parser(self, source, name, encode_filename(filename)).parse()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 896, in parse
    result = nodes.Template(self.subparse(), lineno=1)
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 878, in subparse
    rv = self.parse_statement()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 130, in parse_statement
    return getattr(self, 'parse_' + self.stream.current.value)()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 268, in parse_block
    node.body = self.parse_statements(('name:endblock',), drop_needle=True)
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 165, in parse_statements
    result = self.subparse(end_tokens)
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 878, in subparse
    rv = self.parse_statement()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 130, in parse_statement
    return getattr(self, 'parse_' + self.stream.current.value)()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 198, in parse_for
    body = self.parse_statements(('name:endfor', 'name:else'))
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 165, in parse_statements
    result = self.subparse(end_tokens)
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 870, in subparse
    add_data(self.parse_tuple(with_condexpr=True))
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 615, in parse_tuple
    args.append(parse())
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 427, in parse_expression
    return self.parse_condexpr()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 432, in parse_condexpr
    expr1 = self.parse_or()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 445, in parse_or
    left = self.parse_and()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 454, in parse_and
    left = self.parse_not()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 465, in parse_not
    return self.parse_compare()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 469, in parse_compare
    expr = self.parse_math1()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 491, in parse_math1
    left = self.parse_concat()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 502, in parse_concat
    args = [self.parse_math2()]
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 512, in parse_math2
    left = self.parse_pow()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 523, in parse_pow
    left = self.parse_unary()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 541, in parse_unary
    node = self.parse_primary()
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 578, in parse_primary
    self.fail("unexpected '%s'" % describe_token(token), token.lineno)
  File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 59, in fail
    raise exc(msg, lineno, self.name, self.filename)
jinja2.exceptions.TemplateSyntaxError: unexpected '%'
127.0.0.1 - - [17/Jul/2017 17:26:10] "GET /?__debugger__=yes&cmd=resource&f=style.css HTTP/1.1" 200 -
127.0.0.1 - - [17/Jul/2017 17:26:10] "GET /?__debugger__=yes&cmd=resource&f=jquery.js HTTP/1.1" 200 -
127.0.0.1 - - [17/Jul/2017 17:26:10] "GET /?__debugger__=yes&cmd=resource&f=debugger.js HTTP/1.1" 200 -
127.0.0.1 - - [17/Jul/2017 17:26:11] "GET /?__debugger__=yes&cmd=resource&f=console.png HTTP/1.1" 200 -

浏览器里面的报错信息：

http://localhost:5000/

jinja2.exceptions.TemplateSyntaxError
jinja2.exceptions.TemplateSyntaxError: unexpected '%'

Traceback (most recent call last)
File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1997, in __call__
return self.wsgi_app(environ, start_response)
File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1985, in wsgi_app
response = self.handle_exception(e)
File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1540, in handle_exception
reraise(exc_type, exc_value, tb)
File "/home/henry/.local/lib/python3.5/site-packages/flask/_compat.py", line 33, in reraise
raise value
File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1982, in wsgi_app
response = self.full_dispatch_request()
File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1614, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1517, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/home/henry/.local/lib/python3.5/site-packages/flask/_compat.py", line 33, in reraise
raise value
File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1612, in full_dispatch_request
rv = self.dispatch_request()
File "/home/henry/.local/lib/python3.5/site-packages/flask/app.py", line 1598, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/home/henry/dev/Flask_Web_Python_Henry/flask_henry/app/main/views.py", line 25, in index
return render_template('index.html', form=form, name=session.get('name'), known=session.get('known', False))
File "/home/henry/.local/lib/python3.5/site-packages/flask/templating.py", line 134, in render_template
context, ctx.app)
File "/home/henry/.local/lib/python3.5/site-packages/flask/templating.py", line 116, in _render
rv = template.render(context)
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 1008, in render
return self.environment.handle_exception(exc_info, True)
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 780, in handle_exception
reraise(exc_type, exc_value, tb)
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/_compat.py", line 37, in reraise
raise value.with_traceback(tb)
File "/home/henry/dev/Flask_Web_Python_Henry/flask_henry/app/templates/base.html", line 43, in template
{{% endfor %}}
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 1005, in render
return concat(self.root_render_func(self.new_context(vars)))
File "/home/henry/dev/Flask_Web_Python_Henry/flask_henry/app/templates/index.html", line 1, in top-level template code
{% extends "base.html" %}
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 780, in handle_exception
reraise(exc_type, exc_value, tb)
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/_compat.py", line 37, in reraise
raise value.with_traceback(tb)
File "/home/henry/dev/Flask_Web_Python_Henry/flask_henry/app/templates/base.html", line 43, in template
{{% endfor %}}
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/environment.py", line 497, in _parse
return Parser(self, source, name, encode_filename(filename)).parse()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 896, in parse
result = nodes.Template(self.subparse(), lineno=1)
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 878, in subparse
rv = self.parse_statement()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 130, in parse_statement
return getattr(self, 'parse_' + self.stream.current.value)()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 268, in parse_block
node.body = self.parse_statements(('name:endblock',), drop_needle=True)
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 165, in parse_statements
result = self.subparse(end_tokens)
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 878, in subparse
rv = self.parse_statement()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 130, in parse_statement
return getattr(self, 'parse_' + self.stream.current.value)()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 198, in parse_for
body = self.parse_statements(('name:endfor', 'name:else'))
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 165, in parse_statements
result = self.subparse(end_tokens)
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 870, in subparse
add_data(self.parse_tuple(with_condexpr=True))
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 615, in parse_tuple
args.append(parse())
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 427, in parse_expression
return self.parse_condexpr()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 432, in parse_condexpr
expr1 = self.parse_or()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 445, in parse_or
left = self.parse_and()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 454, in parse_and
left = self.parse_not()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 465, in parse_not
return self.parse_compare()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 469, in parse_compare
expr = self.parse_math1()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 491, in parse_math1
left = self.parse_concat()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 502, in parse_concat
args = [self.parse_math2()]
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 512, in parse_math2
left = self.parse_pow()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 523, in parse_pow
left = self.parse_unary()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 541, in parse_unary
node = self.parse_primary()
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 578, in parse_primary
self.fail("unexpected '%s'" % describe_token(token), token.lineno)
File "/home/henry/.local/lib/python3.5/site-packages/jinja2/parser.py", line 59, in fail
raise exc(msg, lineno, self.name, self.filename)
jinja2.exceptions.TemplateSyntaxError: unexpected '%'
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找到问题的原因了，这一行前后多了【{ }】